CH716145A2 - Method and device for thermal treatment of urban waste. - Google Patents

Abstract

The invention relates to a device (10) for the thermal transformation of waste (100), in particular urban waste, in particular organic waste, plant waste, synthetic materials or the like. It comprises transport means (21), housed in a closed space (22), to discharge them into at least one confined site (23), at least one furnace (24), which contains the confined space (23). The oven (24) consists of a tower (24a) having an outer wall (24b) and a central core (25). A substantially cylindrical inner wall (24c) is mounted parallel to the outer wall (24b) of the tower (24a), to define a first cylindrical space (24d) in which are interposed circuits of electrical convection heating coils (26, 27, 28), which correspond to temperature zones (T1, T2, T3) of the oven. The inner wall (24c) of the cylindrical space (24d) leaves at the periphery of the central core (25) a second cylindrical space which constitutes the confined space (23), crossed by said waste (100)

Description

Technical area

The present invention relates to a process for thermal transformation of waste, in particular urban waste, in particular organic waste, plant waste, synthetic materials or the like, in which a contribution of said waste is carried out in at least one confined site , in the absence of oxygen, with a view to treating them to obtain processed products, in which a significant reduction in their humidity is carried out before and during their penetration into said confined site, and in which a gradual rise in temperature is carried out , by zones of predetermined temperatures, and in that one proceeds, during the continuous movement of said waste, to their vertical settlement by gravity, in said confined site, in said zones of predetermined temperatures.

[0002] It also relates to a device for thermal transformation of waste, in particular of urban waste, in particular of organic waste, of plant waste, of synthetic or similar materials, comprising transport means for carrying out a supply of said waste in at least one confined site, in the absence of oxygen, with a view to treating them to obtain processed products, comprising preheating means for effecting a substantial reduction in their humidity previously and during their penetration into said confined site, heating means for effecting a gradual rise in temperature, by zones of predetermined temperatures, and packing means, to proceed during the continuous movement of said waste, to their vertical packing by gravity in said confined site, through said zones of predetermined temperatures.

Prior art

The treatment of urban waste is a problem that arises in all cities of the world and invades many rural sites, beaches in many countries and currently pushes users to initiate techniques and procedures to avoid a destructive invasion for their agriculture, their environment and their fishing. The very nature of urban waste is heterogeneous and the recovery of recovery products, resulting from the waste, requires, under most of the treatment conditions proposed, an excessively expensive and tedious prior sorting to implement. Waste recovery involves in many areas the implementation of technologies that are too consistent to implement and the temporary destruction of waste still too often consists of either burying the waste, that is to say temporarily masking it or , in more advanced areas, to destroy them for example by incineration. Both cases are both costly and both of these processes cause serious damage to the environment either through water pollution or air pollution. Not only is the correction of the damage caused to the environment resulting from the implementation of landfill or incineration techniques costly, does not constitute a lasting effective solution, but remains economically ineffective for the population which has committed in these steps. The recovery of waste through profitable electrical and thermal energy production remains limited and does not provide an effective solution for a population that produces this waste. In addition, the low storage capacities available to make waste recovery products profitable, as well as their introduction into the consumer network, are currently too limited to be a profitable product.

[0004] The technology of transforming certain waste by pyrolysis undoubtedly constitutes a positive approach to recovering waste, in particular organic waste or waste capable of producing products that provide little or no greenhouse gas, in particular CO2 . However, it remains a large consumer of energy and the presence of water in urban waste has resulted in a limitation of applications to the recovery of tires, synthetic products, in particular of plastic origin and / or dehydrated woody biomass.

[0005] The main recovery of said urban waste and other organic waste is the manufacture of fuel in solid, liquid or gaseous form without CO2 emissions or other greenhouse gases.

However, waste treatment devices remain very segmented for specific applications and treatment units are extremely complex and excessively expensive in terms of energy consumption and maintenance costs. Currently the pyrolysis furnaces, which remain the most targeted in terms of applications, are made for specific applications and are, for the most part incapable of producing, from various wastes, various transformation products for specific applications, at satisfactory costs.

Disclosure of the invention

The present invention proposes to overcome these drawbacks by implementing a method, as defined by the preamble and which responds to all the problems encountered in terms of waste processing, in particular household waste or the like, in terms of production of processed products having a real economic value and capable of being stored without degrading, having a real energy value and delivering a minimum of greenhouse gases, in particular CO2 when used as fuel.

For this purpose, one proceeds to said progressive rise in the temperature of said waste, by predetermined temperature zones, by means of electric induction heating, independent, arranged specifically in each of said predetermined temperature zones and in that said processed products are evacuated at the exits of said confined site, after thermal transformation of said waste as a function of treatment temperatures, in gaseous, liquid or solid form.

[0009] According to a preferred embodiment, said increase in the temperature of said waste is carried out by heating the heat transfer elements which are in direct contact with said waste to be heat treated and which transmit at least part of their heat to them.

[0010] According to an advantageous embodiment, said heat transfer elements comprise wall elements of said confined site, which is crossed by said waste to be thermally treated during their movement.

Preferably, temperature zones are determined corresponding to temperature ranges at which it is intended to raise the temperature of said waste to be thermally transformed as a function of the processed products to be obtained.

In a particularly advantageous manner, the temperature of the waste to be treated is raised to a first dehydration value, which is substantially between 100 and 250 ° C, and preferably between 150 and 200 ° C, then at a second roasting value substantially between 200 and 450 ° C and preferably between 250 and 400 ° C then at a third pyrolysis value, substantially between 300 and 900 ° C and preferably between 250 and 800 ° C.

[0013] Advantageously for the treatment of household waste, relatively diverse, we collect processed products resulting from the transformation of waste in the form of combustible gases, in the form of combustible oils and in the form of solid particles, substantially free of CO2.

[0014] For this purpose also, the device according to the invention is characterized in that said means for heating said waste by zones of predetermined temperatures, comprise at least one electric induction heating equipment, specific to each of said predetermined temperatures, said equipment being independent and, arranged specifically in each of said predetermined temperature zones, and in that the device comprises evacuation means arranged to evacuate said processed products at selective exits from said confined site, after the specialized thermal transformation of said waste .

Particularly advantageously, the device can advantageously comprise at least one furnace, which contains said confined space into which the waste to be transformed is poured, in which the furnace consists of a tower partly of cylindrical shape, and of 'a central core positioned symmetrically inside the tower, induction heating means positioned, at least partially in a first cylindrical space delimited along an outer wall of said tower and said confined space, crossed by said waste to transform thermally during their transformation.

[0016] The predetermined temperature zones are preferably delimited by horizontal sectors positioned from top to bottom, in the direction of movement of the waste during its transformation, which each comprise induction heating means capable of generating an increasing temperature by compared to the previous one corresponding to that of the previous predetermined temperature zone.

The wall of the central core is advantageously a magnetizable material, preferably iron or an iron alloy.

[0018] The outer wall of said tower is advantageously made of a non-magnetic material, in particular aluminum or an aluminum-based alloy.

[0019] The outer wall of said tower is preferably a magnetizable material, preferably iron or an iron alloy.

The induction heating means are preferably positioned in part in the annular space between the outer wall of the tower and the inner wall of said tower and in that the additional induction heating means are housed in said central core.

The oven is constructed according to a principle of interlocking sectors, each of the components of which corresponds to a predetermined temperature zone and in that the components of each individual part of the oven consist of a central sector comprising a central core element, a wall element of the furnace and a set of electric coils arranged to constitute the induction heating means corresponding to the predetermined temperature zone concerned.

In summary, the present invention proposes to overcome the drawbacks of the known prior art, by providing means for processing urban waste delivered in mixed form and summarily sorted, in particular without recyclable materials which can be easily separated such as metals, glass or used batteries, along with organic waste and all other organic waste. In this form, it is possible to produce a solid fuel which allows the massive storage of energy, both electrical, after combustion to supply a generator, and thermal. The fuel is transportable as needed and can be used in conventional burners or transformed into heat and electricity by cogeneration. Part of the solid fuel produced can be used to supply all of the installations according to the invention, for its production.

Brief description of the drawings

The present invention and its main advantages will appear better in the description of a preferred embodiment, with reference to the accompanying drawings in which: FIG. 1 represents a schematic view which illustrates the method and an advantageous embodiment of a device for the transformation of urban waste according to the invention, FIG. 2A represents a view in longitudinal section of a second embodiment of a device for transforming urban waste according to the invention, FIG. 2B represents a cross-sectional view of the device for transforming municipal waste from FIG. 1A, and FIG. 3 represents a view in longitudinal section of a third embodiment of a device for transforming urban waste, comprising a plurality of furnaces for transforming waste, according to the invention,

Best way (s) to carry out the invention

Referring to the figures, and in particular to Figure 1, the waste processing device 10 is arranged to transform household waste 100, which consists in particular of urban waste, in particular organic waste, plant waste, from plastics, from plastics for example thermoplastics or the like to processed products having a reusability, for example in the form of combustible products or products having an own usable functionality. The device 10 comprises on the one hand conveyor means 21, housed in a closed space 22, which may be a conduit or a channel or the like, in which said waste 100 is brought by said conveyor means 21 to discharge them into at least one confined site 23. The space 22 is closed, preferably in a sealed manner, to avoid the presence of waste with air or oxygen and may contain means for reducing their humidity level, in the form of vibrators or the like or any other suitable means.

The transformation device 20 further comprises at least one oven 24, which contains the confined space 23 receiving the waste 100 to be transformed. Very generally, the oven 24 consists of a tower 24a which is partly cylindrical having an outer wall 24b. Inside the tower 24a is arranged a central core 25, positioned symmetrically inside the tower 24a and which is closed so as not to leave any open space that can be crossed by the waste 100. An interior wall 24c substantially cylindrical is mounted parallel to the outer wall 24b of the tower 24a, to define a first cylindrical space 24d in which are interposed circuits of electric coils 26, 27, 28, in particular which correspond to predetermined temperature zones T1, T2, T3 of the oven 24, as will be explained in more detail hereinafter. The inner wall 24c of the cylindrical space 24d leaves at the periphery of the central core 25 a second cylindrical space which constitutes said confined space 23, crossed by said waste 100 to be thermally transformed.

In the example shown, the confined space 23 has the shape of a cylindrical section. However, this cylindrical space produced in one piece could be produced in several cylindrical sections arranged in parallel, for example for reasons of heating the waste, in the passage zones which would then consist of parallel sectors surrounding the central core 25.

The furnace 24 and the central core 25 are, as mentioned above, composed of three sectors T1, T2, T3, but which could be supplemented by complementary sectors Tn-1et Tn, having temperatures different from those of the sectors T1, T2 and T3. In addition, as shown in figure 1, a complementary electric coil circuit sector 35 could be arranged inside central core 25, in the lower part of the oven 24, which corresponds to the hottest zone of predetermined temperatures. , which is for example the sector T3. The complementary circuit of electric coils 35 could for example be arranged in the wall of the central core 25.

In the lower part of the oven 24, three receiving sectors of processed products have been shown. It is for example an evacuation 40 of liquid products such as oil, an evacuation 41 of gases, such as synthetic gases and an evacuation 42, at the base of the oven 24, for solid processed products, such as carbon black or roasted pellets or the like. The processed products are dependent on the nature of the waste 100 treated in treatment temperature zones. Further details will be given in the description of the method according to the invention.

[0029] According to a particularly advantageous form of construction, the oven 24 could be constructed according to a principle of interlocking sectors, each of which corresponds to a predetermined temperature zone, as initially planned. The components of each individual part of the furnace 24 consist of a central sector 35a, 35b, 35c etc ..., comprising a central core element 35, a wall element 24a, 24b, 24c, etc ... of the furnace 24 and an element of circuits of electric coils 26, 27, 28 etc ... arranged to constitute the heating means corresponding to the predetermined temperature zone concerned T1, T2, T3, etc ... In this case, the oven 24 would have a modular design and its maintenance and servicing could be carried out in a simple and efficient manner by a simple replacement of the defective part. The number of independent modules corresponds in this case to the number of individual units which define the predefined temperature zones.

With regard to the sectors of the furnace 24, the heating means of which are controlled by induction, it will be noted that the central core 25 is made of a ferrous material, magnetizable, reacting to the induced electric currents. It is placed in the heart of the furnace 24. As a result, the mass of waste 100 to be treated is directly in contact with the hot mass, which increases the efficiency and the homogeneity of the heating. Indeed, the presence of the central core 25 is added to the presence of the interior wall 24c also made of a ferrous material, magnetizable, reacting to the induced electric currents, to heat the waste 100 to be transformed.

In addition, the heating system thanks to the induction, which acts remotely within the magnetic fields by the generation of induced electric current, does not require any particular maintenance because it does not come into contact with waste in transit.

The waste transformation mode 100, defined by the process, is carried out as follows. During their circulation in the conveyor means 21, the waste 100 preferably has a temperature of between 70 and 90 ° C. Subsequently they undergo vertical settlement by the effect of their gravity and following their partial dehydration on the transport means 21, housed in the closed space 22. This dehydration is essential to the greatest possible extent in order to avoid the production of non-condensable greenhouse gases such as CO2. They enter the confined site 23 to be subjected to predefined temperatures, in the temperature zones T1, T2, and T3, or T1, T2, T3, Tn-1 and Tn. which are gradually increasing from top to bottom. In order to improve and promote the dehydration of the waste 100, a drying hopper can complete the means of transport or can be arranged in the first predetermined temperature zone T1 to raise the temperature of the waste to a first value which can, for example be included between 100 and 250 ° C, and preferably between 150 and 200 ° C. Subsequently, zone T2, called roasting zone, can be arranged so that the temperature is set substantially between 200 and 450 ° C and preferably between 250 and 400 ° C. A third temperature zone, called pyrolysis zone, having a temperature of between 300 and 900 ° C and preferably between 250 and 800 ° C could be provided in the oven of device 10.

According to a preferred operating mode, the chain of operations required according to the method of the invention initially comprises the at least partial dehydration of the waste 100, brought to an uncontrolled temperature and varying between 50 to 100 degrees and preferably between 70 and 90 ° C, in order to remove a portion of free water, and therefore a significant portion of oxygen present in the mass of waste to be treated.

Subsequently, the drying is carried out at a controlled temperature of the waste 100 by the first zone of predetermined temperatures. The energy supplied comes in part from the recovery of waste heat during other operations of the device. A possible additional heat is provided by the electric induction heater.

The temperature roasting controlled by the induction of the oven allows the temperature of the waste 100 to be raised to around 200 and 450 ° C and preferably between 250 and 400 ° C. The energy required comes in part from heat recovery by other thermal waste treatment operations. The second phase of treatment proposed by the innovation is the roasting of the materials to be treated directly following the first treatment or in a deferred manner according to production needs.

The last operational phase relates to the heat treatment by pyrolysis which is carried out at temperatures substantially between 400 and 800 ° C, but which could change depending on the needs and the waste to be transformed.

The products can be delivered in non-condensed gaseous form such as for example the following gases: CH4, C2H4, H2, CO, CO2, or in condensed form, for example pyrolysis oils, usable as fuel to drive a generator electric or in the form of solid residues such as carbon black, pellets which can be used to generate heat or bio char, which can be used in agriculture.

Figures 2A and 2B illustrate views of another embodiment of a device 50 for transforming waste 100 of the urban waste type or the like, mixed. The device 50 comprises, like the device 10, substantially the same elements, constructed and assembled on somewhat different bases. The transformation device 50 comprises at least one oven 54, which contains a confined space 53 receiving the waste 100 to be transformed. The oven 54 is composed like the oven 20 shown in Figure 1, a tower 54a having an outer wall 54b and inside which is disposed a central core 55, which is closed so as to leave no open space that can be traversed by the waste 100. An inner wall 54c is mounted parallel to the outer wall 54b of the tower 54a, to have electrical circuits 56, 57, 28, or more which correspond to predetermined temperature zones T1, T2, T3 of the oven 54. As previously, a second cylindrical space which constitutes said confined space 53 is arranged to be traversed by said waste 100 to be thermally transformed. At the various exits of the confined space 53, respectively 60, 61 and 62 are collected one by one by liquids, for example oils, gases and solids, similar to those mentioned in the description of figure 1.

The cross-sectional view of Figure 2B of the device of Figure 2A along the cutting axis MM, shows that the construction of the oven 50, close to the embodiment of the oven 24 of Figure 1, is substantially cylindrical, with conical and / or tapered inlet and outlet sectors. We see the superposition of the three essential sectors, the electrical sector with the components of electrical circuits responsible for the production of predetermined heat in the predetermined temperature zones, this sector being defined between the outer wall 54a of the oven 50 and its inner wall 54c; the waste passage sector 100, namely the confined space 53 and the central core 55. FIG. 3 represents a form of generalization of the device 50 with n units arranged in series. All the units 50 are arranged side by side under a closed duct 22 for supplying waste 100 to be thermally treated following their passage through the confined spaces 53 arranged around the central cores 55. At the outlet of each of the treatment units, the 100 transformed wastes are collected in the form of liquids, more particularly fuel oils, gases and solids at outlets, respectively 60, 61 and 62.

Theoretically, the treatment temperature zones could be modified by one of the units 50, 51 ... n-1, n. By way of example, one of the units could be essentially or entirely concerned with very high temperatures with the aim of carrying out mainly or exclusively a treatment of the waste 100 by pyrolysis. Another unit could specialize in roasting processing to increase profitability in larger units.

Various variants could be imagined by those skilled in the art, as regards the production and the arrangement of the temperature zones of the device, but they remain included in the characteristics defined by the claims. The system described is a priori used to manufacture solid fuel as well as fuels in liquid or gaseous form with a view to providing hot thermal and electrical energy to consumers from urban waste and other organic waste. However, it is of course conceivable to modify the production parameters according to the specific needs of users and consumers.

Claims (14)

1. Process for the thermal transformation of waste, in particular urban waste, in particular organic waste, plant waste, synthetic materials or the like, in which a contribution of said waste is carried out in at least one confined site, in the absence of oxygen , with a view to treating them to obtain processed products, in which a significant reduction in their humidity is carried out prior to and during their penetration into said confined site, and in which a gradual rise in temperature is carried out, by zones of predetermined temperatures , and in that one proceeds, during the continuous movement of said waste, to their vertical settlement by gravity in said confined site, through said zones of predetermined temperatures, characterized in that one proceeds to said gradual increase of the temperature of said waste, by predetermined temperature zones, by electric induction heating means, independent, available specifically dared in each of said predetermined temperature zones and in that said processed products are evacuated at the exits of said confined site, after thermal transformation of said waste according to treatment temperatures, in gaseous, liquid or solid form . 2. Method according to claim 1, characterized in that said increase in the temperature of said waste is carried out by heating heat transfer elements which are in direct contact with said waste to be thermally treated and which transmit at least part of their heat to them. . 3. Method according to claim 2, characterized in that said heat transfer elements comprise wall elements of said confined site, which is crossed by said waste to be thermally treated during their movement in said confined site. Said increase in the temperature of said waste is carried out by heating heat transfer elements which are in direct contact with said waste to be thermally treated and which transmit at least part of their heat to them. 4. Method according to any one of claims 1 to 3, characterized in that one determines temperature zones corresponding to temperature ranges at which it is expected to raise the temperature of said waste to be thermally treated depending on the products. processed to obtain. 5. Method according to claim 4, characterized in that the temperature of the waste to be treated is raised to a first dehydration value, which is substantially between 100 and 250 ° C, and preferably between 150. and 200 ° C, then at a second roasting value substantially between 200 and 450 ° C and preferably between 250 and 400 ° C then at a third pyrolysis value, substantially between 300 and 900 ° C and preferably between 250 and 800 ° C. 6. Method according to claim 5, characterized in that one collects the processed products resulting from the transformation of waste in the form of combustible gases, in the form of combustible oils and in the form of solid particles, substantially free of CO2. . 7. Device for thermal transformation of waste, in particular urban waste, in particular organic waste, plant waste, synthetic materials or the like, comprising means of transport for carrying out said waste in at least one confined site, in the absence oxygen, with a view to thermally treating them to obtain processed products, this device comprising desiccation means for effecting a substantial reduction in their humidity previously and during their penetration into said confined site, heating means for effecting an elevation progressive temperature, by zones of predetermined temperatures, and packing means, to proceed during the continuous movement of said waste, to their vertical settlement by gravity in said confined site, through said zones of predetermined temperatures, characterized in that said means for heating said waste by predetermined temperature zones born, comprise at least one electric induction heating equipment, specific to each of said predetermined temperatures, said equipment being independent and, arranged specifically in each of said predetermined temperature zones, and in that the device comprises evacuation means arranged to evacuate said processed products at selective outlets from said confined site, after specialized thermal processing of said waste. 8. Device according to claim 7, characterized in that it comprises at least one furnace (24), which contains said confined space (23) into which are discharged the waste (100) to be transformed, in which the furnace (24) consists of a tower (24a) partly cylindrical in shape, and a central core (25), positioned symmetrically inside the tower (24a), the induction heating means positioned, at least partially in a first cylindrical space (24d) delimited along an outer wall (24b) of said tower (24a) and said confined space (23), crossed by said waste during their transformation. 9. Device according to claims 7 or 8 characterized in that the predetermined temperature zones are delimited by horizontal sectors (T1, T2, T3, Tn-1et Tn) positioned from top to bottom, in the direction of movement of the waste at the during their transformation, which each comprise induction heating means (26, 27, 28, 35) capable of generating an increasing temperature with respect to the previous one. 10. Device according to claim 7, characterized in that the wall of the central core (25) is a magnetizable material, preferably iron or an iron alloy. 11. Device according to claim 7, characterized in that the outer wall (24b) of said tower (24) is made of a non-magnetic material, in particular aluminum or an aluminum-based alloy. 12. Device according to claim 7, characterized in that the outer wall (24c) of said tower (24) is a magnetizable material, preferably iron or an iron alloy. 13. Device according to claims 7 or 8, characterized in that the heating means (26, 27, 28) by induction are positioned in part in the annular space between the outer wall (24b) of the tower (24 ) and the inner wall (24c) of said tower (24) and in that the additional heating means (35) by induction are housed in said central core. 14. Device according to claim 7, characterized in that the oven (24) is constructed according to a principle of interlocking sectors, each of the components of which corresponds to a predetermined temperature zone and in that the components of each individual part of the oven (24 ) consist of a central sector comprising a central core element, a furnace wall element and a set of electric coils arranged to constitute the heating means corresponding to the predetermined temperature zone concerned.